1. Field of the Invention
This invention relates generally to tools used to complete subterranean wells. More particularly the present invention describes a shifting tool that can be used to actuate a downhole device.
2. Description of Related Art
Hydrocarbon fluids such as oil and natural gas are obtained from a subterranean geologic formation, referred to as a reservoir, by drilling a well that penetrates the hydrocarbon-bearing formation. Once a wellbore has been drilled, the well must be completed before hydrocarbons can be produced from the well. A completion involves the design, selection, and installation of equipment and materials in or around the wellbore for conveying, pumping, or controlling the production or injection of fluids.
While completing a well or performing subsequent remedial work, downhole tools requiring mechanical actuation are often used. The mechanical actuation can be used to perform numerous types of actions, for example, setting or releasing a downhole tool or reconfiguring a tool, such as opening or closing a valve.
Shifting tools of various kinds are commonly used in the industry and known to those skilled in the art. In general a shifting tool allows a force exerted on the shifting tool to be transferred to a separate downhole tool, thus providing the needed force to operate a mechanical actuation. A simple example of a shifting tool used to perform a mechanical actuation would be a tool having a set of jars and a contact device having a profile, the tool being used to shift a sliding sleeve into a different position. The contact device profile can be sized to pass through the well tubulars but to land on a reduced diameter profile of the sliding sleeve. The contact device and jars can be run into the well until the contact device profile lands on the sliding sleeve profile, force from the jars can then be transferred through the contact device onto the sliding sleeve profile, thus imparting force onto the sliding sleeve and moving the sliding sleeve to a different configuration.
A problem that is frequently confronted is the need to pass a shifting tool through well tubulars having reduced interior diameters. The simple example described above would not work below a tubular having a reduced diameter. One means that has been employed to overcome this problem has utilized expandable elements such as inflatable packers that can pass through the restricted diameter portion in a deflated position. Once in its desired location, the packer element can be inflated to a sufficient extent that it sets within the downhole tool and can then be used as a shifting tool to transfer force and enable the mechanical actuation of the downhole tool. Once the actuation has been completed, the inflatable element can be deflated and removed from the well. A drawback to the use of inflatable elements for this application is the possibility that the inflatable element will not deflate to the extent needed to pass through the restricted diameter upon removal from the well. If the expandable element does not deflate fully or if it is damaged in some way it may not be possible to remove the shifting tool from the well. If this happens the restricted diameter tubular may have to be removed from the well or even more extensive and costly recovery measures taken.
Another prior art means of engaging a downhole tool below a restriction involves utilizing an expanding mechanical shifting tool having slip elements located in the same plane. After the shifting tool has passed through the restriction, the tool can then be expanded to a larger diameter in an attempt to engage the downhole tool. This type of shifting tool has limitations on the extent of expansion that can be achieved.
Despite the use of prior art features, there remains a need for an improved expandable shifting tool.
One embodiment of the present invention is an expandable shifting tool comprising a housing having an outer surface and a plurality of radially extendable elements longitudinally separated from each other. The extendable elements are capable of moving between an extended position and a retracted position. The extendable elements can be at least partially contained within the housing and can be biased towards the extended position.
The extendable elements can comprise a first surface and a second surface, the first surface comprising an end of the extendable element that protrudes outside of the housing outer surface when in its extended position. When in the fully retracted position the first surface extends no further axially than the outer surface of the housing. The second surface of the extendable element extends no further axially than the housing outer surface when the extendable element is in its retracted position. The housing can comprise a wall having openings that enable the second surface of the extendable element to be located within the wall opening when the extendable element is in its retracted position. Each extendable element is capable of protruding beyond the housing outer surface a distance greater than 50 percent of the housing outer surface diameter length. Each extendable element can be located on the opposite side of the tool from an adjacent extendable element.
The housing may be cylindrical in shape, and the shifting tool can comprise a first and second end, having at least one passageway capable of communicating fluid between the first end and the second end within the shifting tool housing. The first end can comprise a connection that is capable of connecting to deployment device while the second end can comprise fluid outlet ports capable of discharging fluid from the passageways through the tool. The extendable elements and tool housing may comprise alignment elements that guide the extendable elements as they move between their retracted and extended positions. Each extendable element is capable of moving between the retracted and extended position independent of any other extendable element. The first surface of the extendable element can comprise a profile that is capable of engaging a mating profile. Each extendable element first surface profile can be different than the first surface profiles of the other extendable elements.
Another embodiment is a shifting tool comprising a generally cylindrical housing having a wall, an outer diameter, a first end and a second end. A plurality of anchor slips at least partially located within the housing and comprising an first surface and a second surface, are located in separate radial planes from each other and are capable of moving independently between a retracted position and an extended position. At least one longitudinal passageway is within the housing capable of providing hydraulic communication between the first end and the second end of the tool. The anchor slips in their extended position are each capable of extending beyond the outer diameter of the housing a distance in excess of 50 percent of the housing diameter.
The anchor slips can be biased towards the extended position and comprise alignment elements that guide the anchor slips as they move between their retracted and extended positions. In their retracted position the anchor slips do not extend beyond the outer diameter of the tool housing in some embodiments. The tool housing can comprise openings within its wall that are capable of containing a portion of the second surface of an anchor slip when the anchor slip is in its retracted position.
Yet another embodiment is a shifting tool comprising a generally cylindrical housing comprising a wall and an outer diameter. A plurality of latching members are at least partially disposed within the housing, the latching members being capable of moving independently between an inner position and an outer position, thereby defining a tool diameter. When the latching members are in their outer position the tool diameter is capable of being in excess of 150 percent of the housing diameter. The shifting tool can also contain latching members comprising a profile that is capable of engaging a mating profile, each latching member profile can be different than the other latching member profiles. The latching members may be biased to the outer position with a spring element and comprise alignment lugs that guide the latching members as they move between their inner and outer positions.
Each latching member can be located in separate radial planes from the other latching members. When a latching member is in its inner position, it is possible for the latching member to be contained within the housing outer diameter. The housing wall may comprise openings wherein when a latching member is in its inner position a portion of the latching member is located within the opening of the housing wall. At least one passageway can exist longitudinally through the tool within the housing providing fluid communication through the tool. The tool can comprise a first end and a second end, the first end having a coupling capable of connecting to a deployment device and the second end comprising at least one nozzle capable of discharging fluid from the at least one passageway.
Still another embodiment of the present invention is a downhole assembly comprising a shifting tool and a downhole profile. The shifting tool comprises a housing having an outer diameter and a plurality of radially extendable slips longitudinally separated from each other. Each slip is at least partially contained within the housing, outwardly biased and capable of acting independently. The downhole profile is adapted to releasably engage with the shifting tool. The shifting tool slips may comprise a profile that engages with a matching profile contained in the downhole profile. The shifting tool may comprise at least one fluid passageway within its housing capable of communicating fluid through the shifting tool.
One embodiment of the invention is a method of actuating a downhole tool comprising providing an expandable shifting tool comprising a plurality of axially extending elements that are longitudinally separated from each other. The shifting tool is inserted within the downhole tool and a profile on the extending elements engages with a matching profile on the downhole tool. Force is then applied to the shifting tool that is transferred to the downhole tool, thus actuating the downhole tool. The extending elements can be biased in an outward position and each extending element may have a different profile than the other extending elements. The shifting tool can comprise at least one passageway whereby fluid can be circulated through the shifting tool to wash the shifting tool down to the downhole tool.
Yet another embodiment is an apparatus comprising a housing and a plurality of slip elements longitudinally spaced from each other and capable of extending radially from the housing. Each slip comprises a profile that is capable of engaging a matching downhole profile. The slip elements are capable of being spaced at about 90 to about 180 degree phasing from the adjacent slip elements. The apparatus can comprise a first end and a second end and at least one passageway capable of communicating fluid between the first end and the second end within the apparatus housing.
Still another embodiment is a method of actuating a downhole tool by providing an expandable shifting tool comprising a plurality of radially extending elements that are longitudinally separated from each other. The shifting tool is inserted within the downhole tool where a profile on the extending elements engage with a matching profile on the downhole tool. Force is applied to the shifting tool that is transferred to the downhole tool, thus actuating the downhole tool. The extending elements can be biased in an outward position and each extending element can have a different profile than the other extending elements. The shifting tool can comprise at least one passageway whereby fluid can be circulated through the shifting tool to wash the shifting tool down to the downhole tool.
Another embodiment is a method of actuating a downhole tool located below a restricted diameter tubular comprising providing an expandable and collapsible mechanical shifting tool. The shifting tool comprising a plurality of outwardly biased slips, the slips spaced in radially separated planes. The shifting tool is inserted through the restricted diameter tubular and to the downhole tool. The slips of the shifting tool engage with the downhole tool. Movement of the shifting tool actuates the downhole tool, after which the shifting tool is disengaged from the downhole tool and passes through the restricted diameter tubular. The outer surfaces of the slips may comprise a profile that is capable of releasably engaging with a matching profile in the downhole tool. Each slip may comprise a profile with a different pattern than the other slips. Fluid may be circulated through at least one passageway within the shifting tool to wash the shifting tool down to the downhole tool.
Yet another embodiment of the invention is a method of actuating a downhole tool located in a wellbore that is deviated from vertical. This method comprises providing an expandable shifting tool comprising a housing having an outer diameter and at least two extendable dog elements. Each dog element is capable of extending beyond the housing outer diameter. The shifting tool is inserted into the wellbore, engaged with the downhole tool and the downhole tool is actuated. The shifting tool can be located eccentrically within the downhole tool. Fluid may be circulated through at least one passageway within the shifting tool to wash the shifting tool down to the downhole tool. The extendable dog elements may comprise a profile that releasably engages with a matching profile on the downhole tool. One side of the shifting tool can be in contact with the downhole tool, but each dog element is capable of engaging with the matching profile on the downhole tool.